As noted, the book contains the "Night Hours" - AKA Mattins, or the Office of Readings. St. Margaret's very likely doesn't pray Mattins today - few modern orders do - but this is certainly of historical interest. John Mason Neale founded this order during the revitalization of Anglican Orders in the 19th Century. Perhaps more on that interesting topic later.

I thought I'd include the whole Preface to this volume here; I have a great deal of respect for monastics and religious - and I find it fascinating to take a look back into the history of these orders and see things from the point of view of earlier generations.

The third instalment of Night Hours, now at last completed, must be prefaced by a few words in explanation of its variations from the two former volumes.

So difficult and so tentative is the whole work of preparing ancient offices for English use at the present day, that mistakes and imperfections could hardly be avoided, especially on the part of editors so inexperienced as those to whom the task, since Dr. Neale's death, has been committed; although much valuable help has most kindly been afforded them. But the history of the book is as follows.

On first founding his Sisterhood at East Grinsted, Dr. Neale felt it of the first importance to supply its members with offices of prayer. He considered the use of S. Osmund to be that alone, which, as English, it was our duty to adopt, but the Sarum Breviary was not within his reach, except in the partial reprint, by Mr. Leslie, which included the Psalter and ferial office, but not much more. He seems, therefore, to have translated the ferial day office from Mr. Leslie's book; but he took the Night Hours from the reformed Roman, inserting a Gallican office here and there when it pleased him better than the Roman. As long as the work was manuscript, and intended only for the use of one House, this eclecticism was, of course, perfectly allowable.

Not long before his death, he planned the publication of a translated Sarum Breviary, in which, however, the Lectionary was to be exchanged for that of the reformed Roman, on account of the revision undergone by the latter, to which the former, from the circumstances of the sixteenth century, never was subjected.

This plan, however, was not carried into effect. After our Founder was taken to rest, we were urged to publish the Matin offices he had given us; and we did so, filling up the blanks left by him with insertions from the same (Roman) book from which he had translated (as, for instance, the lessons of the third nocturns, which he had been wont to turn into English extempore, when saying the office). And thus we prepared the first and second volumes, and proposed, in a third, to print the offices for black-letter days.

After a time the Sarum Breviary was placed in our hands, and we were requested, on behalf of other Beligious Houses, to render its Day Offices into English, as exactly as might be practicable. Dr. Neale had laid the foundation for this by his abridged translation of the ferial and Sunday office over twenty years ago. Propers of Seasons and Saints were now added, and an office book was produced, essentially Sarum, though containing, as noted in its Preface, certain modifications which appeared desirable.

This being done, a considerable discrepancy became visible between our Night and Day Offices, and chiefly in the Services for Saints' Days. The Night Office for the Common of Seasons may be considered as nearly identical in the Roman and Sarum books, except that the responsories do not follow in the same order, that every Sarum office of nine lessons has nine responses, and that no office throughout Easter-tide has more than one nocturn of three psalms, three lessons and three responses: and as far as the Common of Seasons is concerned, the Roman Night Office can, quite practicably, be used together with the Sarum Day Office. But this cannot be done in the case of Saints' Days without producing a sense of dislocation. The present offices, therefore, are so arranged as to fit those for the day hours in our Breviary Offices, and have the same identity with Sarum and the same divergencies from it; the Lectionary being taken, in great measure, from the Boman Breviary, but supplemented from other sources and containing some of the old Sarum lessons, especially in the Octave of the Holy Name.

It will be a satisfaction to those who use this book if we set down in order the sources of the various offices.

From the Sarum, except usually the lessons, are: S. Andrew, Conversion of S. Paul, Annunciation, S. John Baptist, SS. Peter and Paul, Commemoration of S. Paul, S. Peter's Chains (except Invitatory), Transfiguration, Holy Name, S. Laurence, Repose of the Blessed Virgin, (abridged), Beheading of S. John Baptist, SS. Matthew and Luke, S. Michael and All Angels and All Saints. In the Conception of the Blessed Virgin, Invitatory, Antiphon, and Responses are Gallican. S. Thomas of Canterbury has the Common of a Martyr, instead of his Proper: S. Agnes, the Common of a Virgin Martyr, instead of Proper: (lessons of the second nocturn, from the Roman office for her feast). Purification; Inv. and Ants., Gallican: Responses; Sarum, (last Response abridged). Invention of the Cross. first Nocturn, Sarum. This festival falling in Easter-tide, has but one nocturn according to Sarum; but ae this practice is not carried out in the Easter-tide offices of vols. 1 and 2, other two nocturns are added: the third from the office of the Exaltation of the Cross, on which feast the second nocturn is devoted to the commemoration of a martyr: the second nocturn is therefore here drawn from a Carmelite breviary assimilating strongly with the Sarum. Visitation: Ants. and some Responses and lessons, Sarum: the rest Roman and Gallican. S. Mary Magdalene: Hymn and Ants., Sarum: Responses, Gallican, except Response 9, which is Sarum. Nativity of the Blessed Virgin: Gallican: except Response 9, which is Sarum. Guardian Angels: Roman. The rest are of the Common.

The Rev. Gerard Moultrie has been good enough to translate several hymns for this book, in their original metre.

A suggestion respecting the Kalendar was made and carried out by our learned friend, the Rev. F. LI. Bagshawe. It was his idea that, without presuming beyond our province, a Kalendar might be introduced into these office books which should present to the mind some view of Church history, and more especially of the history of the British Church: containing the names of Saints of primitive times and universal celebrity, of those who most notably taught and upheld the faith in our own country; and of the founders and reformers of religious orders. These added names are commemorated, by memorial only, at Vespers and Lauds in the forthcoming edition of the Breviary Day Offices; in which also the black-letter days of the Prayer Book Kalendar are similarly commemorated, when their full office does not occur in this present volume. It has seemed desirable to prefix the Kalendar, as thus arranged, to this book as well as to the Breviary Offices, in order to assimilate them for the convenience of persons in the habit of using the latter. Matin offices are given in this volume for those festivals alone which are commemorated with full day office in the other.

When a second edition of the first and second volumes of Night Hours appears, a body of Sarum rubrics will, it is hoped, be inserted : meanwhile, those in the Breviary Offices may suffice for the use of persons desirous of following Sarum practice; while others will without difficulty continue to use the Roman rubrics as already set down in volumes 1 and 2.

A few points should be mentioned.

The Sarum hymn for Common of Apostles is Annue Christe. This is inserted here for optional use : the Roman hymn, Eterna Christi munera, is to be found in the Common Office, vols. 1 and 2.

A ninth Response is supplied throughout, also for optional use, and a note at end of Appendix points out that which belongs to the Common of Apostles.

Te Deum, said on festivals in Advent according to the Roman use, was wholly omitted in the Sarum book during that season.